1. Circulating exosomal RNA as a biomarker in melanoma.
Association of Women Surgeons
October 15th, 2016
Genevieve M. Boland, MD, PhD
Assistant Professor, Harvard Medical School
Assistant in Surgery, Massachusetts General Hospital

2. A lot has changed in a very short period of time.

3. Molecularly-targeted therapy

4. Immunotherapy

5. Circulating Biomarkers in Cancer
CTCs
ctDNA
Exosomes
Proteins
Westphal et al. 2015

6. Exosomes: Defined By Size
Bence Gyorgy et al. Cell. Mol. Life Sci. 2011
AETHLON MEDICAL INC
Exosomes express a sub-proteome of the cell.
Exosomes encapsulate mRNA that can be transferred to other cells to modulate the recipients’ transcriptome.
Exosomes “carry” hundreds of miRNAs that could interfere with up to thousands of mRNAs.

7. Exosomes in Cancer
Bobrie et al, 2011

8. RNA is Concordant: Cells vs Exosomes
Allele Fraction (%)
RPMI 7951 Cells
RPMI 7951 Exo
A375 Cells
A375 Exo
Sk mel 2 Cells
Sk mel 2 Exo
Sk mel 30 Cells
Sk mel 30 Exo
MeWo Cells
MeWo Exo
BRAF V600E NRAS Q61R NRAS Q61K

9. Patient-Derived Exosome Characterization*
p<0.0001
400
300
200
100
Exosome Concentration x107
Normal Melanoma
pg BRAF V600E/ng RNA
Pt Number
Definitive Rsxn
Palliative Rsxn
Electron Microscopy
pg BRAF V600E/ng RNA
Pre-resection
Post-resection
Patient Number
Pt Number

10. RNA is Concordant: Tumor vs Exosomes
Immune/Hematologic
Metabolic

11. Exosome Profile Reflects Response to aPD1
Pre- and On-treatment exosomes (n=20) of responders and non-responders to aPD1
Statistically significant differences (p<0.05) in pre- to on- change between responders and non-responders
111 genes, including 8 miRNA and markers of immune activation
(e.g. IFN-gamma)
Expansion cohort and validation ongoing

12. Exosome RNA Correlates with Tumor Mutations
BRAF
Exosomal RNA
NRAS
Triple WT
We are in the midst of a remarkable time in cancer drug development. As a melanoma oncologist and researcher, I have had the remarkable opportunity to see the treatment landscape change dramatically over the past several years. This slide graphically depicts this change over time…
NF1
CKIT

13. Immunotherapy: predictive signature of response to aPD1
Immunotherapy responsive
Exosomal RNA
We are in the midst of a remarkable time in cancer drug development. As a melanoma oncologist and researcher, I have had the remarkable opportunity to see the treatment landscape change dramatically over the past several years. This slide graphically depicts this change over time…
Immunotherapy non-responsive

14. Future Directions
Examine the use of tumor mutations to assess minimal residual disease and identify a high-risk subset of surgical patients
Expand the cohort of immunotherapy patients to validate our immunotherapy response signature
Clinical trial of the use of exosomes as a marker of high-risk or residual disease is surgically resected melanomas
Clinical trial of exosomal profiling to predict/correlate with response to immunotherapy

15. Acknowledgements Boland Lab, MGH Flaherty Lab, MGH Collaborators:
Bill Michaud, PhD
Sonia Cohen, MD, PhD
Jessica Cintolo-Gonzalez, MD
Ali Rabi, MD, PhD
Roman Alpatov, PhD
Tabea Moll, MS
Flaherty Lab, MGH
Marc Hammond
Hans Vitzhum
Deborah Plana
Benchun Miao, PhD
Collaborators:
Fisher Lab, CBRC, MGH
David Panka, PhD, BIDMC
Soldano Ferrone, MD, PhD, MGH
Darrell Borger, PhD, MGH
Ryan Corcoran, MD, PhD, MGH
Nir Hacohen, PhD, MGH/Broad Institute
Manolis Kellis, PhD, MIT/Broad Institute
Larry Zhang
Alvin Shi, PhD